1) Field of the Invention
The present invention relates to an image formation apparatus that has a plurality of writing optical units.
2) Description of the Related Art
Recently, the trend is that the image formation apparatuses such as copying machines and printers output color images. Moreover, there is a great demand for small sized and high speed image formation apparatus. An image formed by a color copying machine that employs a electrostatic copying system is formed by combining color toners of Y (yellow), M (magenta), C (cyan), Bk (black), or the like. According to the color copying machine, the significant characteristic of the color electrostatic copying system depends on whether the image formation with the colors is executed by the time series process or the concurrent process.
As to the discussion on the upper limit of the output number (for example, the number of outputs in copying or printing papers of a predetermined size in a unit time) among the performances of the image formation apparatus, it is known that the concurrent process system provides a value higher than that of the time series process. That is, although an image formation apparatus with a small size and low cost concurrent processing system mounted is required in the market, since a plurality of latent images should be processed at the same time in the image formation apparatus of the concurrent processing system, it is necessary to provide an image formation section including a writing optical device in the same number as that of the concurrent processes for forming the latent image.
However, according to the concurrent processing system, not all the image formation sections are operated at the time of all the image formations. For example, when a monochrome image is formed, only a section controlling the Bk image formation is operated without the need of the other image formation sections. Moreover, according to the concurrent processing system, when a writing optical device has failed or broken down (hereinafter xe2x80x9cbroken downxe2x80x9d), a printing operation cannot be executed until the writing optical device is repaired even in the case of printing a single color image so as to require a pause period of the image formation apparatus. Furthermore, for example, according to a two color image formation apparatus with monochrome and another color functions, due to the limitation of the structure, or the like, the equivalent writing performance may not be provided to both of the image formation sections.
It is an object of this invention to at least solve the problems in the conventional technology.
The image formation apparatus according to one aspect of the present invention comprises a photosensitive member; a charging device that charges the photosensitive member; a charge eliminating device that eliminates a residual charge from the photosensitive member before the charging device charges the photosensitive member; and a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. In this construction, a latent image formed by the writing optical device of the first image formation section is processed to be a visual image by the developing device of the second image formation section.
The image formation apparatus according to another aspect of the present invention comprises a photosensitive member; a charging device that charges the photosensitive member; a charge eliminating device that eliminates a residual charge from the photosensitive member before the charging device charges the photosensitive member; and a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. In this construction, a first latent image of a first set of pixels is formed by the writing optical device of the first image formation section in a main scanning direction, a second latent image of a second set of pixels is formed between the pixels of the first set of pixels by the writing optical device of the second image formation section, and a visual image of the first latent image and the second latent image is formed by the developing device provided in any one of the first image formation section and the second image formation section.
The image formation apparatus according to still another aspect of the present invention comprises a photosensitive member; a charging device that charges the photosensitive member; a charge eliminating device that eliminates a residual charge from the photosensitive member before the charging device charges the photosensitive member; and a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. In this construction, a latent image of different pixels lines in a main scanning direction is formed at different positions in a sub scanning direction by the writing optical devices of each of the first image formation section and the second image formation section on a surface of the photosensitive member, and a visual image of the latent images is formed by the developing device provided in any one of the first image formation section and the second image formation section.
The image formation method according to still another aspect of the present invention is a method of forming an image by an image formation apparatus, the image formation apparatus having a first image formation section and a second image formation section, each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. The method comprises forming a latent image by the writing optical device of the first image formation sections; and forming a visual image of the latent image by the developing device of the second image formation section.
The image formation method according to still another aspect of the present invention is a method of forming an image by an image formation apparatus, the image formation apparatus having a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. The method comprises judging whether the writing optical device in the first image formation section is broken down; forming the latent image by the writing optical device of the second image formation section when it is judged that in the first image formation section is broken down; and forming the visual image of the latent image by the developing device of the first image formation section.
The image formation method according to still another aspect of the present invention is a method of forming an image by an image formation apparatus, the image formation apparatus having a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image, wherein a gradation expressing ability of the writing optical device of the first image formation section is lower than a gradation expressing ability of the writing optical device of the second image formation section. The method comprises forming the latent image by the writing optical device of the second image formation section; and forming the visual image of the latent image by the developing device of the first image formation section.
The image formation method according to still another aspect of the present invention is a method of forming an image by an image formation apparatus, the image formation apparatus having a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. The method comprising forming a first latent image of a first set of pixels by the writing optical device of the first image formation section in a main scanning direction; forming a second latent image of a second set of pixels between the pixels of the first set of pixels by the writing optical device of the second image formation section; and forming a visual image of the first latent image and the second latent image by the developing device provided in any one of the first image formation section and the second image formation section.
The image formation method according to still another aspect of the present invention is a method of forming an image by an image formation apparatus, the image formation apparatus having a first image formation section and a second image formation section each of the first image formation section and the second image formation section having a writing optical device that forms a latent image on a surface of the photosensitive member, and a developing device that forms a visual image by adhering a developing agent on the latent image. The method comprising forming a latent image of different pixels lines in a main scanning direction at different positions in a sub scanning direction by the writing optical devices of each of the first image formation section and the second image formation section on a surface of the photosensitive member; and forming a visual image of the latent images by the developing device provided in any one of the first image formation section and the second image formation section.
The computer program according to still another aspect of the present invention realizes the image formation method on an image formation apparatus.
These and other objects, features and advantages of the present invention are specifically set forth in or will become apparent from the following detailed descriptions of the invention when read in conjunction with the accompanying drawings.